Dial operating apparatus

ABSTRACT

When a knob dial  18  is turned on, a predetermined LED  15   c  to  15   e  corresponding to a rotational position of the knob dial  18  is turned on. Then, a beam of light is supplied to a predetermined indicator lens  29   a  to  29   f  via a predetermined light path  30,  and the indicator lens  29   a  to  29   f  can be illuminated. In this structure, the optical path  30  is formed into a sector-shape. Therefore, even if the knob dial  18  is set at an intermediate position, the beam of light emitted from LED  15   c  to  15   e  is supplied to the indicator lens  29   a  to  29   f  via the optical path  30.  Accordingly, the indicator lens  29   a  to  29   f  can be illuminated to the utmost.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

The present invention relates to a dial operation device having astructure for informing an operator of a rotational position of a knobdial when a plurality of display sections provided in the knob dial areselectively illuminated.

2. Technical Background

FIG. 7 is a view showing a conventional structure of the above dialoperation device. In this structure, a knob base 2 is fixed onto aprinted circuit board 1. A knob dial 3 is attached onto an outercircumferential surface of this knob base 2. This knob dial 3 isprovided with a plurality of linear light paths 3 a. In the knob dial 3,there are provided a plurality of display sections 4 arranged at one endportion of each light path 3 a, and these display sections 4 transmitlight.

On the printed wiring board 1, there are provided a plurality of lightsources 5 which are located on a rotational locus of the display section4. When the knob dial 3 is rotated for operation along an outercircumferential surface of the knob base 2, electricity is supplied to apredetermined light source 5 according to a rotational position of theknob dial 3, so that light can be supplied to a predetermined displaysection 4 via a predetermined light path 3 a. Then, the predetermineddisplay section 4 is illuminated. When a plurality of marks 2 a on theknob base 2 are selectively indicated, a rotational condition of theknob dial 3 is conveyed to an operator.

However, the following problems may be encountered in the aboveconventional structure. When the knob dial 3 is set at an intermediateposition at which the display section 4 and the light source 5 are notopposed to each other, a beam of projection light sent from the lightsource 5 is intercepted by the knob dial 3. Therefore, no light issupplied to the display section 4. Therefore, light can not be suppliedto the display sections 4 in the middle of rotation of the knob dial 3.

SUMMARY OF THE INVENTION

The present invention has been accomplished in view of the abovecircumstances. It is an object of the present invention to provide adial operation device capable of illuminating a display section to theutmost even in the middle of rotation of the knob dial.

A dial operation device described in claim 1 comprises a knob dial to berotated for operation; a plurality of display sections capable oftransmitting light, arranged in the knob dial; a plurality of lightsources arranged on rotational loci of the plurality of displaysections; a control unit for selectively turning on a light source inthe plurality of light sources according to a rotational position of theknob dial; and a plurality of light paths for supplying light, which hasbeen projected by the light sources, to the display sections, arrangedin the knob dial, wherein these light paths are formed into asubstantial sector-shape, the width of which is extended from the lightexit to the light entrance.

According to the above means, the light path is formed into asubstantial sector-shape, and width of the light path is extended fromthe light exit to the light entrance. Due to the above structure, evenif the knob dial is set at an intermediate position, a beam ofprojection light sent from the light source is projected into the lightentrance except for an instant at which a wall section located betweenthe light paths is opposed to the light source. Therefore, the beam oflight can be supplied to the display section via the light path, so thatthe display section can be illuminated to the utmost.

In the dial operation device described in claim 1, the control unitoperates in such a manner that when the knob dial starts being rotated,a light source corresponding to the next rotational position is turnedon while a light source corresponding to the rotational position of thedial knob remains on.

According to the above means, when the knob dial starts being rotated, alight source corresponding to the rotational position of the knob dialis turned on, and a light source corresponding to the next rotationalposition of the knob dial is turned on. Therefore, a beam of projectionlight sent from the light source corresponding to the next rotationalposition is supplied to the display section via the light path.Accordingly, the display section corresponding to the next rotationalposition of the knob dial is illuminated, and a rotational direction ofthe knob dial is conveyed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing a first embodiment of the present invention,that is, FIG. 1 is a perspective view showing a knob dial;

FIG. 2 is a front surface view showing a heater controller;

FIG. 3 is a transversely cross-sectional view showing the heatercontroller;

FIG. 4 is a front view showing a printed wiring board;

FIG. 5 is an exploded perspective view showing the heater controller;

FIG. 6 is a view corresponding to FIG. 5 in which a second embodiment ofthe present invention is shown; and

FIG. 7 is a view corresponding to FIG. 1 in which a conventional exampleis shown.

THE MOST PREFERRED EMBODIMENT

Referring to FIGS. 1 to 5, the first embodiment of the present inventionwill be explained as follows. In this connection, this embodiment is acase in which the present invention is applied to a heater controller ofan automobile, and this heater controller is attached onto an instrumentpanel of the automobile. As shown in FIG. 3, there is provided a bezel32 made of synthetic resin. This bezel 32 is formed into a rectangularbox-shape, the rear surface of which is open. A printed wiring board 12is attached to the bezel 32 with screws, and a rear opening of the bezel32 is covered with a printed wiring board 12 and a cover 11.

As shown in FIG. 5, holders 13, 13 made of synthetic resin are attachedonto the front surface of the printed wiring board 12. As shown in FIG.1, each holder 13 has six partition walls 13 a which are integrated withthe holder 13. Only four partition walls 13 a are shown in FIG. 5.Between the partition walls 13 a, there is formed an LED accommodatingsection 13 b.

As shown in FIG. 4, two common circuit patterns 14, which are formedinto an arc-shape, are formed on the front surface of the printed wiringboard 12. As shown in FIGS. 2 and 5, LEDs 15 a to 15 e corresponding tolight sources are accommodated in five LED accommodating sections 13 bof each holder 13. One of the terminals of each LED is connected to thecommon circuit pattern 14.

As shown in FIG. 4, on the front surface of the printed wiring board 12,there are provided five power source circuit patterns 16 which arelocated in an outer circumferential section of each common circuitpattern 14. The other terminal of each LED is connected to the powersource pattern 16. Electricity is supplied to LEDs 15 a to 15 e via thecommon circuit pattern 14 and the power source circuit pattern 16.

Knob bases 17, 17 shown in FIG. 5 are made of synthetic resin. Acylindrical section 17 a is integrally formed in each knob base 17. Eachcylindrical section 17 a corresponds to a moderation member and has ahexagonal cross-section as shown in FIG. 2. As shown in FIG. 3, there isformed a hole 12 a at the center of the holder 13 on each printed wiringboard 12. A screw is inserted into the hole 12 a from the rear side.This screw 17 b is screwed into the cylindrical section 17 a. Due to theforegoing, the knob bases 17, 17 are fixed onto the printed wiring board12.

As shown in FIG. 5, a substantially cylindrical knob dial 18 made ofsynthetic resin is pivotally engaged on an outer circumferential surfaceof each knob base 17. On an inner circumferential surface of the knobdial 18, there are formed three grooves not shown in the drawing. In theknob dial 18, there is accommodated a cylindrical knob body 19 made ofsynthetic resin.

On an outer circumferential surface of the knob body 19, threeprotrusions 19 a are integrally formed as shown in FIG. 5. The threeprotrusions 19 a of the knob body 19 are engaged with the grooves of theknob dial 18. Therefore, when the knob dial 18 is rotated for operation,torque is transmitted to the knob body 19 via the three protrusions 19a, and the knob body 19 is integrally rotated. In this connection, asshown in FIG. 3, a plurality of spherical sections 21 a are formed on alower surface of each knob dial 18 and on a lower surface of each knobbody 19. Due to the above structure, when each knob dial 18 is rotatedfor operation, the plurality of spherical sections 21 a slide on theprinted wiring board 12.

As shown in FIG. 2, a leaf spring 22 corresponding to the spring memberis accommodated in each knob body 19. Each leaf spring 22 is bent andformed into a triangle. In each leaf spring 22, there are formed threeengaging sections 22 a. As shown in FIG. 5, there are formed threegrooves 19 b on an inner circumferential surface of each knob body 19.The engaging sections 22 a of the leaf spring 22 are inserted into thethree grooves l9 b of each knob body 19. Due to the above structure,when each knob dial 18 is rotated for operation, the leaf spring 22 isrotated integrally with the knob body 19.

As shown in FIG. 2, three surfaces of each leaf spring 22 come intosurface-contact with predetermined three surfaces of the cylindricalsection 17 a. Therefore, when each knob dial 18 is rotated and the leafspring 22 is operated according to the rotation of the knob dial 18, theleaf spring 22 is pushed and deflected by three corners of thecylindrical section 17 a. After that, the three corners of eachcylindrical section 17 a get over the leaf spring 22 and engage withthree new surfaces, so that the rotation of each knob dial 18 can beregulated again. Accordingly, each knob dial 18 can be positioned at theinterval of 60°. Further, each time the corners of the cylindricalsection 17 a get over the leaf spring 22 at the interval of 60°, it ispossible to provide a feeling of moderation.

As shown in FIG. 3, a contact 23 located on the outer circumference isscrewed onto a rear surface of each knob dial 18. As shown in FIG. 5,each contact 23 has contact points 23 a to 23 d. The contact points 23a, 23 b on the outer circumferential side come into contact with thecommon circuit pattern 14, the shape of which is an arc as shown in FIG.4.

On the front surface of the printed wiring board 12, there are providedfirst detection circuit patterns 24 a to 24 e which are located on theinner circumferential section of each common circuit pattern 14. Wheneach knob dial 18 is rotated for operation, the contact point 23 c ofeach contact 23 comes into the detection circuit pattern 24 a to 24 eaccording to the rotational position of the knob dial 18. Due to theforegoing, the predetermined detection circuit pattern 24 a to 24 e canbe selectively continued to the common circuit pattern 14, and acontinuation signal is outputted from the predetermined detectioncircuit pattern 24 a to 24 e. In this connection, the contact point 23 bof each contact 23 is a dummy contact point which is provided foradjusting the mechanical balance.

An ECU (not shown) corresponding to a control unit is mounted on anautomobile. This ECU is mainly composed of a microcomputer and operatedas follows. A rotational position of each knob dial 18 is detectedaccording to the detection circuit pattern 24 a to 24 e from which acontinuation signal is outputted. A hot air or cold air blowing positionof air control is changed over according to a rotational position of theknob dial located on the left, and a quantity of blowing control air ischanged over according to a rotational position of the knob dial 18located on the right. At the same time, electricity is supplied to apredetermined LED 15 a to 15 e via the common circuit pattern 14 and thepower supply circuit pattern 16, so that light can be emitted from thepredetermined LED 15 a to 15 e.

As shown in FIG. 2, there are provided a plurality of marks 25indicating a blowing position of hot air on the front surface of theknob base 17 located on the left, and there are provided a plurality ofmarks 26 indicating a quantity of blowing hot air on the front surfaceof the knob base 17 located on the right. These marks 25, 26 are formedon the knob base 17 by means of laser beam machining and may transmitlight.

As shown in FIG. 3, there is provided a light guide 27 at the rear ofthe printed wiring board 12 in the cover 11. As shown in FIG. 4, thereare provided openings for illumination at the rear of the marks 25, 26on the printed wiring board 12. In the light guide 27, there areprovided protrusions 27 a at the rear of the openings 12 b forillumination.

As shown in FIG. 3, there are provided a plurality of lamps 28 on therear surface of the printed wiring board 12. These lamps 28 arepositioned in the light guide 27. When the plurality of lamps 28 aresupplied with electricity by the controlling operation of the ECU, lightis emitted from the protrusions 27 a so that the marks 25, 26 can beilluminated via the openings 12 b for illumination.

As shown in FIG. 1, an indicator lens 29 a to 29 f is embedded at afront end portion on a circumferential wall of each knob dial 18. Theseindicator lenses 29 a to 29 f correspond to the display sections. LEDs15 a to 15 e are positioned at the rear of the indicator lenses 29 a to29 f, that is, LEDs 15 a to 15 e are positioned on the locus ofrotation. Therefore, as shown in FIG. 2, under the condition that theknob dials 18 are positioned, five predetermined indicator lenses in theindicator lenses 29 a to 29 f are opposed to LEDs 15 a to 15 e. In thisconnection, the indicator lenses 29 a to 29 f are formed on the knobdials 18 by means of two color formation.

As shown in FIG. 1, there are provided six light paths 30 on thecircumferential wall of each knob dial 18. Each light path 30 connects alight entrance 30 a, which is open via a rear surface of the knob dial18, with a light exit 30 b which is communicated with the indicator lens29 a to 29 f. Each light path 30 is formed into a sector-shape in whichwidth is gradually extended from the light exit 30 b to the lightentrance 30 a. In this connection, reference numeral 30 c is a lightshielding wall section located between the light paths 30.

Under the condition that a position of each knob dial 18 is regulated,each light shielding wall section 30 c is opposed to a partition wall 13a of the holder 13. Accordingly, a beam of light projected from apredetermined LED 15 a to 15 e passes through the light exit 30 a andthe light entrance 30 b and is supplied to a predetermined indicatorlens 29 a to 29 f. Due to the foregoing, the predetermined indicatorlens 29 a to 29 f emits light. Therefore, a plurality of marks 25, 26are selectively indicated. Accordingly, a hot air blowing position and aquantity of hot air to be blown out by the knob dial are conveyed to adriver.

As shown in FIG. 4, on the front surface of the printed wiring board 12,there are provided second detection circuit patterns 31 _(a1), 31 _(a2)to 31 _(e1), 31 _(e2) which are located on an inner circumference of thefirst detection circuit patterns 24 a to 24 e. Under the condition thata position of each knob dial 18 is regulated, the contact point 23 d ofthe contact 23 is located in a gap between the detection circuitpatterns 31 _(a1), 31 _(a2) to 31 _(e1), 31 _(e2) as shown by two-dottedchain lines.

Accordingly, when each knob dial 18 is rotated for operation, thecontact point 23 d of the contact 23 comes into contact with thedetection circuit pattern 31 _(a1), 31 _(a2) to 31 _(e1), 31 _(e2)according to the rotational direction of the knob dial 18. Therefore,the detection circuit pattern 31 _(a1), 31 _(a2) to 31 _(e1), 31 _(e2)can be selectively continued to the common circuit pattern 14. Then, asdescribed later, the ECU determines a rotational direction of each knobdial 18 according to the detection circuit pattern 31 _(a1), 31 _(a2) to31 _(e1), 31 _(e2) from which a continuity signal has been outputted.

The bezel 32 shown in FIG. 5 is made of synthetic resin. As shown inFIG. 3, a plurality of engaging holes 32 a are formed on a side plate ofthe bezel 32. In this case, only one engaging hole 32 a is illustratedin the drawing. A plurality of claws 11 a are integrally formed on aside plate of the cover 11. In this case, only one claw 11 a isillustrated in the drawing. When the bezel 32 is pushed onto the outsideof the cover 11, each engaging holes 32 a are engaged with the claw 11a, so that the bezel 32 can be attached to the cover 11, and the frontsurface of the printed wiring board 12 is covered with the bezel 32.

In this connection, as shown in FIG. 5, there are formed two circularopenings 32 b in the bezel 32. As shown in FIG. 3, each knob dial 18protrudes from the opening 32 b onto the front surface side.

As shown in FIG. 5, on the front surface of the printed wiring board 12,there is provided a base 33 which is arranged between holders 13. In theuppermost portion of this base 33, there are provided rubber contactpoints 34 a, 34 b to turn on and off the defrosting mode in whichcontrolled air is blown out onto a windshield. In the middle portion ofthis base 33, there are provided rubber contact points 34 a, 34 b toturn on and off the REC mode in which air is circulated in a chamber. Inthe lowermost portion of this base 33, there are provided rubber contactpoints 34 a, 34 b to turn on and off an air conditioner.

In the bezel 32, there is formed a rectangular opening 32 c. Into thisrectangular opening 32 c, three operation knobs 35 are attached as shownin FIG. 2. When each knob 35 is pushed for operation, the ON-signal isoutputted from the rubber contact points 34 a and 34 b.

Each operation knob 35 is provided with an indicator lens 35 a. As shownin FIG. 3, on the printed wiring board 12, there is provided an LED 35 bwhich is arranged in each operation knob 35. According to the operatingcondition of the operation knob 35, the ECU turns on and off LED 35 b,so that each indicator lens 35 a can be turned on and off. Therefore, adriver is informed of the operating condition (defrosting mode, REC modeand setting condition of the air conditioner) of each operation knob 35.

As shown in FIG. 2, on the right of the bezel 32, there is provided aknob dial 36 which is pivotally attached. According to a rotationalposition of the knob dial 36, ECU adjusts a temperature of controlledair.

In the bezel 32, there is provided an operation key 36 a which isarranged inside the knob dial 36. When ECU detects an operation in whichthe operation key 36 a is pushed, the automatic control mode is turnedon and off. In the automatic control mode, a blowing position ofcontrolled air and a quantity of controlled air can be automaticallychanged over. At the same time, when electricity is selectively suppliedto LED 15 a to 15 e irrespective of the rotational position of each knobdial 18, light is emitted from a predetermined indicator lens 29 a to 29f via the light entrance 30 a and light exit 30 b. Due to the foregoing,a changeover condition in which a position of blowing air and a quantityof blowing air are changed over can be conveyed to a driver.

In the bezel 32, there are provided panels 37 a and 37 b. On the panels37 a and 37 b, there are respectively provided indicator lenses 38 a and38 b. When the LED (not shown) is turned on and off by the ECU, theindicator lenses 38 a, 38 b are turned on and off. Therefore, theoperating condition (setting condition of the automatic control mode) ofthe operation key 36 a can be conveyed to the driver.

Next, the action of the above arrangement will be explained below. Afterthe automatic control mode of an air blowing position and the automaticcontrol mode of a quantity of controlled air have been turned off, eachknob dial 18 is rotated for operation. Due to the above operation, theECU controls so that electricity can be supplied to LED 15 a to 15 eaccording to the rotational position of each knob dial 18 and apredetermined indicator 29 a to 29 f can be turned on. Accordingly, aplurality of marks 25, 26 are selectively indicated. Due to theforegoing, the driver is informed of a rotational condition (hot airblowing position and quantity of hot air) of each knob dial 18.

At the same time, while electricity is being supplied to LED 15 a to 15e according to the rotational position of the knob dial 18, electricityis supplied to an adjacent LED 15 a to 15 e in the rotational directionof the knob dial 18. Due to the foregoing, the rotational direction ofthe knob dial 18 is conveyed to the driver.

For example, as shown by two-dotted chain lines in FIG. 4, before theoperation of each knob dial 18, the contact point 23 c of each contact23 comes into contact with the first detection circuit pattern 24 c.Under the above condition, the detecting circuit pattern 24 c and thecommon circuit pattern 14 are electrically continued to each other.Therefore, a continuation signal is outputted from the detecting circuitpattern 24 c. Accordingly, when the ECU controls such that electricitycan be supplied to LED 15 c in FIG. 2, a beam of light is supplied tothe indicator lens 29 c via the light entrance 30 and the light exit 30b, and light is emitted from the indicator lens 29 c.

When the knob dial 18 is rotated for operation in the direction of arrowA under the above condition, the contact point 23 d of the contact 23comes into contact with the second detecting circuit pattern 31 _(c2) inFIG. 4, and a continuity signal is outputted from the second detectingcircuit pattern 31 _(c2). Then, the ECU determines that a rotationaloperation in which the knob dial 18 is rotated in the direction of arrowA has been started. Therefore, in FIG. 2, electricity is supplied to LED15 d which is adjacent to LED 15 c in the direction of arrow A, and LED15 c and LED 15 d are simultaneously turned on.

When LED 15 c and LED 15 d are turned on, a beam of projection lightsent from LED 15 c is supplied to the indicator lens 29 c via the lightentrance 30 a and the light exit 30 b. Therefore, the light emittingcondition of the indicator lens 29 c remains. At the same time, a beamof projection light sent from LED 15 d is supplied to the indicator lens29 d via the light entrance 30 a and the light exit 30 b. Therefore,light is emitted from the indicator lens 29 d.

After that, the contact point 23 c of the contact 23 comes into contactwith the first detecting circuit pattern 24 d in FIG. 4, and acontinuity signal is outputted from the first detecting circuit pattern24 d. Then, the ECU turns off LED 15 c in FIG. 2. Then, a beam ofprojection light sent from LED 15 d is supplied to the indicator lens 29c via the light entrance 30 a and the light exit 30 b. Therefore, onlythe indicator lens 29 c emits light.

In the above embodiment, when the leaf spring 22 is engaged with threesurfaces of the cylindrical section 17 a, the rotation of the knob dial18 is regulated. Therefore, when the knob dial 18 is operated and theleaf spring 22 is rotated, the leaf spring 22 is pushed by three cornersof the cylindrical section 17 a and bent in the same direction as thatof pushing. For the above reasons, the rotational resistance of the knobdial 18 is reduced, and an operation feeling of the knob dial 18 becomeslight. It is possible to prevent the operation feeling from growingheavy especially at an intermediate position.

In this embodiment, the light path 30 is formed into a sector-shape inwhich width of the light path 30 is extended from the light exit 30 b tothe light entrance 30 a. Therefore, even when the knob dial 18 is set atan intermediate position, that is, even when the position of the knobdial 18 is not regulated, a beam of projection light sent from LED 15 ato 15 e is projected into the light entrance 30 a except for an instantat which the light shielding wall section 30 c is opposed to LED 15 a to15 e. Then, the beam of projection light is supplied to the indicatorlens 29 a to 29 f via the light path 30. Therefore, the indicator lens29 a to 29 f can be illuminated to the utmost.

When the rotational operation of the knob dial 18 is started, whileelectricity is being supplied to LED 15 a to 15 e according to therotational position of the knob dial 18, LED 15 a to 15 e adjacent to itin the rotational direction of the knob dial 18 is supplied withelectricity. Therefore, the rotational direction of the knob dial 18 isconveyed to a driver, and the dial operation device becomes more handy.

When the leaf spring 22 is engaged on three surfaces of the cylindricalsection 17 a, rotation of the knob dial 18 is regulated. Therefore, whenthe leaf spring 22 is rotated according to the operation of the knobdial 18, the leaf spring 22 is pushed by three corners of thecylindrical section 17 a and deflected in the direction. Due to theforegoing, rotational resistance of the knob dial 18 is reduced, and afeeling of operation of the knob dial 18 becomes light. It is possibleto prevent a feeling of operation from growing heavy especially at anintermediate position.

Next, referring to FIG. 6, the second embodiment of the presentinvention will be explained below. In this connection, like referencecharacters are used to indicate like parts in the first and the secondembodiment, and the explanations are omitted here. Only parts of thesecond embodiment different from the first embodiment will be explainedas follows. In the knob body 19 arranged on the left, there are providedtwo wire springs 39 which correspond to spring members. In the knob body19 arranged on the right, there is provided one wire spring 39 whichcorresponds to a spring member.

Each wire spring 39 described above is bent into a triangle. In eachwire spring 39, there are formed three engaging sections 39 a. Eachengaging section 39 a is inserted into a groove 19 b of the knob body19. Rotation of the knob dial 18 arranged on the left is regulated whentwo wire springs 39 are engaged with three surfaces of the cylindricalsection 17 a. Rotation of the knob dial 18 arranged on the right isregulated when one wire spring 39 is engaged with three surfaces of thecylindrical section 17 a.

In the above embodiment, when the knob dial 18 arranged on the left isrotated for operation, two wire springs 39 are rotated. Then, the wiresprings 39 are pushed against three corners of the cylindrical section17 a and deflected in the direction. After that, when three corners ofthe cylindrical section 17 a get over the wire springs 39 and new threesurfaces are engaged with two wire springs 39, rotation of the knob dial18 is regulated. Due to the foregoing, rotational resistance of the knobdial 18 is reduced. Accordingly, a feeling of operation of the knob dial18 becomes light, and rotation of the knob dial 18 is prevented fromstopping in the middle of operation. Further, different from the firstembodiment in which the leaf spring 22 is used as a spring member, thewire spring 39 is used in the second embodiment. Therefore, height ofthe knob dial 18 can be decreased.

When the knob dial 18 arranged on the right is rotated, one wire spring39 is rotated. Then, the wire spring 39 is pushed against three cornersof the cylindrical section 17 a and bent in the direction. After that,when three corners of the cylindrical section 17 a get over the wiresprings 39 and new three surfaces are engaged with the wire springs 39,rotation of the knob dial 18 is regulated. Due to the foregoing,rotational resistance of the knob dial 18 is reduced. Accordingly, afeeling of operation of the knob dial 18 becomes light, and rotation ofthe knob dial 18 is prevented from stopping in the middle of operation.Further, since the wire spring 39 is used as a spring member, height ofthe knob dial 18 can be decreased.

Two wire springs 39 are used for the knob dial 18 arranged on the left,and one wire spring 39 is used for knob dial 18 arranged on the right.Therefore, an intensity of the knob dial 18 arranged on the left isdifferent from an intensity of the knob dial 18 arranged on the right.Accordingly, it is possible for a driver to distinguish between the twoknob dials 18 by a feeling of operation. Therefore, the operationproperty of the knob dial 18 can be enhanced.

In this connection, in order to make an intensity of the knob dial 18arranged on the left to be different from an intensity of the knob dial18 arranged on the right in the first embodiment described before, it isnecessary to adjust a spring force by changing heights of both leafsprings 22. Therefore, it is necessary to carefully distinguish betweenboth leaf springs 22 so as to attach them to the knob dials 18, whichtakes labor and time.

In order to improve the above circumstances, the wire springs 39, thenumbers of which are different from each other, are used for both knobdials 18. Therefore, it is unnecessary to carefully distinguish betweenboth leaf springs 22 when they are attached to the knob dials 18.Accordingly, the assembling property can be enhanced. Unlike a case inwhich the leaf springs 22 of different types are manufactured, only onetype wire spring 39 is used in this embodiment. Therefore, thisembodiment is advantageous in that the number of parts can be reduced.

In the above second embodiment, two wire springs 39 are accommodated inthe knob body 19 arranged on the left, and one wire spring 39 isaccommodated in the knob body 19 arranged on the right. However, itshould be noted that the present invention is not limited to the abovespecific embodiment. The number of the wire springs 39 may be adjustedif necessary.

In the above second embodiment, wire spring 39 are accommodated in bothknob bodies 19. However, it should be noted that the present inventionis not limited to the above specific embodiment. For example, when boththe leaf spring 22 and the wire spring 39 are accommodated, intensitiesof forces to operate both knob dials 18 may be adjusted.

In the above first and the second embodiment, the second detectioncircuit patterns 31 _(a1), 31 _(a2) to 31 _(e1), 31 _(e2) for detectingthe rotational directions of the knob dials 18 are formed on the printedwiring board 12. However, it should be noted that the present inventionis not limited to the above specific embodiment. For example, the seconddetection circuit patterns 31 _(a1), 31 _(a2) to 31 _(e1), 31 _(e2) maybe abolished. In this structure, the contact point of each contact 23may be also abolished.

In the above first and the second embodiment, the cylindrical section 17a is fixed to the holder 13, and the leaf spring 22 and the wire spring39 are rotated integrally with the knob dial 18. However, it should benoted that the present invention is not limited to the above specificembodiment. For example, the leaf spring 22 or the wire spring 39 may befixed to the holder 13, and the cylindrical section 17 a may be rotatedintegrally with the knob dial 18.

In the above first and the second embodiment, the cylindrical section 17a, the cross-section of which is hexagonal, the triangular leaf spring22 and the wire spring 39 are used and three surfaces of the cylindricalsection 17 a are engaged with the leaf spring 22 and the wire spring 39.However, it should be noted that the present invention is not limited tothe above specific embodiment. For example, a linear leaf spring andwire spring may be used, and one surface of the cylindrical section 17 amay be engaged with the leaf spring and the wire spring.

In the above first and the second embodiment, a rotational position ofthe knob dial 18 is regulated at the regular interval of 60°. However,it should be noted that the present invention is not limited to theabove specific embodiment. For example, a rotational position of theknob dial 18 may be regulated at the regular interval of 30°. In thisstructure, a cross-section of the cylindrical section 17 a may be formedinto a dodecagon, and the leaf spring 22 and the wire spring 39 may beformed into hexagons.

In the above first and the second embodiment, the present invention isapplied to a heater controller of an automobile. However, it should benoted that the present invention is not limited to the above specificembodiment. The essential point is that the present invention can beapplied to all dial operation devices having rotational knob dials.

As can be understood from the above explanations, the dial operationdevice of the present invention can provide the following effects.

According to the means described in claim 1, the light path is formedinto a sector-shape in which width of the light path is extended fromthe light exit to the light entrance. Due to the above structure, evenif the knob dial is set at an intermediate position, a beam ofprojection light can be supplied to the display section from the lightsource via the light path. Accordingly, the display section can beilluminated to the utmost.

According to the means described in claim 2, while the light sourcecorresponding to the rotational position of the knob dial is beingturned on, the light source of the next rotational position is turnedon. Therefore, the display section corresponding to the next rotationalposition of the knob dial is illuminated. Accordingly, it is possible toconvey a rotational direction of the knob dial to an operator.

What is claimed is:
 1. A dial operation device comprising: a knob dialto be rotated for operation; a plurality of display sections capable oftransmitting light, arranged in the knob dial; a plurality of lightsources arranged on rotational loci of the plurality of displaysections; a control unit for selectively turning on a light source inthe plurality of light sources according to a rotational position of theknob dial; and a plurality of light paths for supplying light, which hasbeen projected by the light sources, to the display sections, arrangedin the knob dial, wherein these light paths are formed into asubstantial sector-shape, the width of which is extended from a lightexit to a light entrance.
 2. The dial operation device described inclaim 1, wherein the control unit operates in such a manner that whenthe knob dial starts being rotated, a light source corresponding to thenext rotational position is turned on while a light source correspondingto the rotational position of the dial knob remains on.